Work around tox-docker KeyError on Docker 29+#862
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jonathangreen merged 1 commit intomainfrom Feb 12, 2026
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Docker 29 removed the deprecated top-level NetworkSettings.Gateway key from the container inspect API, causing tox-docker to fail with a KeyError. Setting TOX_DOCKER_GATEWAY bypasses the broken lookup.
This was referenced Feb 12, 2026
dbernstein
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## Description Added `TOX_DOCKER_GATEWAY` environment variable to the test workflow to work around a `KeyError: 'Gateway'` failure in tox-docker when running on Docker 29+. Docker 29 [removed the deprecated top-level `NetworkSettings.Gateway` key](https://docs.docker.com/engine/release-notes/29/) from the container inspect API. tox-docker 5.0.0 relies on this key and crashes with a `KeyError`. Setting `TOX_DOCKER_GATEWAY=0.0.0.0` bypasses the broken lookup entirely. This became flaky starting Feb 12 as the [Docker 29 rollout](actions/runner-images#13474) to GitHub Actions runners progresses. Once complete, tests will fail 100% of the time without this fix. This workaround can be removed once [tox-docker merges the fix](tox-dev/tox-docker#196). Mirrors the fix applied in [circulation#3045](ThePalaceProject/circulation#3045) and [library-registry#862](ThePalaceProject/library-registry#862). ## Motivation and Context CI test runs are failing intermittently with: ``` tox_docker/plugin.py, line 53, in get_gateway_ip ip = container.attrs["NetworkSettings"]["Gateway"] or "0.0.0.0" KeyError: 'Gateway' ``` ## How Has This Been Tested? - CI will validate that tests pass with the workaround on Docker 29+ runners ## Checklist - [x] I have updated the documentation accordingly. - [x] All new and existing tests passed.
jonathangreen
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## Description Added `TOX_DOCKER_GATEWAY` environment variable to the test workflow to work around a `KeyError: 'Gateway'` failure in tox-docker when running on Docker 29+. Docker 29 [removed the deprecated top-level `NetworkSettings.Gateway` key](https://docs.docker.com/engine/release-notes/29/) from the container inspect API. tox-docker 5.0.0 relies on this key and crashes with a `KeyError`. Setting `TOX_DOCKER_GATEWAY=0.0.0.0` bypasses the broken lookup entirely. This became flaky starting Feb 12 as the [Docker 29 rollout](actions/runner-images#13474) to GitHub Actions runners progresses. Once complete, tests will fail 100% of the time without this fix. This workaround can be removed once [tox-docker merges the fix](tox-dev/tox-docker#196). Mirrors the fix applied in [library-registry#862](ThePalaceProject/library-registry#862). ## Motivation and Context CI test runs are failing intermittently with: ``` tox_docker/plugin.py, line 53, in get_gateway_ip ip = container.attrs["NetworkSettings"]["Gateway"] or "0.0.0.0" KeyError: 'Gateway' ``` ## How Has This Been Tested? - CI will validate that tests pass with the workaround on Docker 29+ runners ## Checklist - [x] I have updated the documentation accordingly. - [x] All new and existing tests passed.
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Description
Added
TOX_DOCKER_GATEWAYenvironment variable to the test workflow to work around aKeyError: 'Gateway'failure in tox-docker when running on Docker 29+.Docker 29 removed the deprecated top-level
NetworkSettings.Gatewaykey from the container inspect API. tox-docker 5.0.0 relies on this key and crashes with aKeyError. SettingTOX_DOCKER_GATEWAY=0.0.0.0bypasses the broken lookup entirely.This became flaky starting Feb 12 as the Docker 29 rollout to GitHub Actions runners progresses. Once complete, tests will fail 100% of the time without this fix.
This workaround can be removed once tox-docker merges the fix.
Motivation and Context
CI test runs on Python 3.14 (and occasionally 3.12/3.13) are failing intermittently with:
How Has This Been Tested?
Checklist